CN115711921A - Pd-TiO 2 Application in preparation of hydrogen and/or methane sensor - Google Patents

Pd-TiO 2 Application in preparation of hydrogen and/or methane sensor Download PDF

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CN115711921A
CN115711921A CN202110970120.4A CN202110970120A CN115711921A CN 115711921 A CN115711921 A CN 115711921A CN 202110970120 A CN202110970120 A CN 202110970120A CN 115711921 A CN115711921 A CN 115711921A
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tio
hydrogen
methane
gas
sensor
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付志华
叶晓亮
徐刚
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Fujian Institute of Research on the Structure of Matter of CAS
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Fujian Institute of Research on the Structure of Matter of CAS
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Abstract

The application discloses a Pd-TiO 2 Use of surface-coordinated TiO atoms based on single Pd atoms for the production of hydrogen and/or methane sensors 2 The method can quickly detect methane and/or hydrogen at a lower temperature, shows excellent sensitivity and reliable stability, reduces energy consumption, and is safer and more environment-friendly.

Description

Pd-TiO 2 Application in preparation of hydrogen and/or methane sensor
Technical Field
The application relates to Pd-TiO 2 The application in preparing hydrogen and/or methane sensor belongs to the field of gas sensor technology.
Background
Methane emissions and leaks are not only detrimental to air quality, resulting in global warming, but also have an impact on many industries and applications. For example, it is critical to detect methane leaks during natural gas production, transportation, and power generation. In the chemical industry, the production of methanol, syngas, acetic acid and other commercial chemicals all rely on methane gas sensors to confirm whether the production process is operating efficiently and safely. In the production, processing, transportation, use and other links of the coal industry, dangerous gases such as gas explosion, toxic gas leakage explosion prevention and the like in each link need to be detected and monitored. In addition, natural gas (the main component is methane) is often widely used as fuel in production life, but accidents caused by natural gas leakage occur frequently, so that it is important to measure the methane level in the atmosphere to monitor changes of environmental conditions, and when the fuel containing the main component of methane is used, the gas leakage is strictly detected and monitored in the processes of production, transportation and storage, so as to avoid potential safety hazards and ensure the safety of life and property of enterprises, staff and the masses!
The problems of hydrogen as fuel come from inevitable hydrogen leakage during production, storage and use of hydrogen fuel cells, and are easy to cause dangers such as hydrogen station explosion, chemical plant fire, environmental impact and the like. Such as hydrogen station explosions, chemical plant fires, fuel cells, environmental influences, etc. In view of the wide use and insecurity of hydrogen in the fields of food hygiene, energy power, military, national defense and the like, the concentration of hydrogen must be detected when the hydrogen is used. To ensure the safety of future hydrogen-fueled vehicles and associated infrastructure, minute levels of hydrogen in the air must be detected, and the response speed of the hydrogen sensor must be fast enough to detect leaking hydrogen before a fire occurs.
The chemical resistance sensor is a real-time detection technology and has the advantages of high sensitivity, high response speed, convenient operation, low production cost and the like. Wherein the representative sensing material Metal Oxide (MO) generally requires higher operating temperatures (generally>250 deg.C) to promote reactive oxygen species (O) 2 - 、O - And O 2 - ) For sensing the reaction. However, the high operating temperature not only increases the risk of fire when detecting combustible gases, but also complicates the manufacture of the apparatus and increases the energy consumption. The loading of metal nanoparticle catalysts with catalytic activity is one of the most common methods for improving the room temperature sensing performance. However, metal nanoparticles generally have relatively low catalytic activity at ambient room temperature conditions. Meanwhile, many factors such as different crystal planes of the metal nanoparticles, synergy of adjacent metal atoms, and uneven distribution of different metal atoms in the alloy nanoparticles may result in multiple catalytically active sites that can simultaneously activate various analytes and reduce their selectivity. Currently, the sensitivity and selectivity of MOs supported metal NP catalysts at room temperature is still unsatisfactory.
The monatomic catalyst has high catalytic activity and selectivity, and has great potential in various catalyst-related applications such as energy source and organic conversion. The single-atom catalyst can almost reach 100% of atom utilization rate, and can realize higher catalytic efficiency. In addition, surface coordinated monatomic catalysts have pure, isolated and structurally identifiable catalytically active sites. And the influence of the nitrogen atom catalyst on different reactants can be flexibly adjusted through the selection of metal atoms, the substitution of a supporting substrate and the change of the coordination environment of the metal atoms. Unfortunately, the development of gas sensitive materials based on monatomic catalysts is still in the beginning and the previous work still requires additional heating, which complicates device fabrication.
Disclosure of Invention
According to one aspect of the present application, there is provided a Pd-TiO 2 Use of surface coordinated TiO atoms based on single Pd atoms for the production of hydrogen and/or methane sensors 2 The method can quickly detect methane and/or hydrogen at a lower temperature, shows excellent sensitivity and reliable stability, reduces energy consumption, and is safer and more environment-friendly.
Pd-TiO 2 Application of Pd-TiO in preparation of hydrogen and/or methane sensor 2 Including Pd monoatomic and TiO 2
The Pd monoatomic atom is coordinated on the TiO 2 Of the surface of (a).
Alternatively, the single Pd atom is a +1 valent Pd single atom 1
Alternatively, the TiO 2 The appearance of (A) is nano flower.
Alternatively, the TiO 2 The particle diameter of (A) is 100 to 500nm.
Alternatively, the TiO 2 Is selected from any one of 100nm, 200nm, 300nm, 400nm, 500nm or a range between any two of them.
Alternatively, the Pd-TiO 2 Wherein the load of the Pd monoatomic atom is 0.1 to 5wt.%.
Optionally, the loading of the Pd monoatomic species is selected from any one of 0.1wt.%, 0.2wt.%, 0.3wt.%, 0.4wt.%, 1wt.%, 2wt.%, 3wt.%, 4wt.%, 5wt.%, or a range value between any two of the values.
Optionally, the detection condition of the sensor includes:
the temperature is 20-30 ℃.
Optionally, the temperature is selected from any one of 20 ℃, 23 ℃,25 ℃, 26 ℃, 28 ℃, 30 ℃ or a range between any two values.
Optionally, the detection condition of the sensor includes:
the temperature is 23-26 ℃.
Optionally, the detection condition of the sensor includes:
the bias voltage is 1-5V.
Optionally, the bias voltage is selected from any one of 1V, 2V, 3V, 4V, 5V or a range between any two values.
Optionally, the detection condition of the sensor includes:
detecting the airflow of 200-600 mL min -1
Optionally, the detection gas flow is selected from 200mL min -1 、300mL min -1 、400mL min -1 、 600mL min -1 Or any range between any two values.
Alternatively, the sensor has a detection limit for methane as low as 0.815ppm at 25 ± 1 ℃;
the limit of detection of the sensor for hydrogen is as low as 0.35ppm.
Alternatively, the Pd-TiO 2 The preparation method comprises the following steps:
will contain TiO 2 And the mixture of Pd salt and the mixture is irradiated for 3-8 min under ultraviolet light to obtain the Pd-containing material.
Optionally, the Pd salt comprises H 2 PdCl 4
Optionally, the power density of the ultraviolet light is 5-12 mW cm -2 The wavelength is 298-415 nm.
As one embodiment, the application provides a method for realizing normal-temperature hydrogen and methane detection by using single Pd atomic group TiO coordinated on the surface 2 Nanometer flower (Pd) 1 -TiO 2 ) The material can detect hydrogen and methane at room temperature, so as to improve the safety and sensitivity of hydrogen and methane detection and reduce energy consumption.
In order to overcome the limitation of sensitivity of the room temperature chemical resistance type sensing material in the aspects of hydrogen and methane sensing in room temperature use, the surface coordinated single Pd atomic group TiO is used for the first time 2 Nanometer flower (Pd) 1 -TiO 2 ) And detecting hydrogen and methane with high activity at room temperature. The Pd monoatomic atoms significantly enhanced TiO compared to Pd nanoparticles (Pd NPs) 2 Sensing performance at room temperature. The work can open a general way for designing new generation of hydrogen and methane sensing materials and equipment, and the materials and the equipment urgently need to construct environmental detection of the Internet of things.
As an embodiment, the technical problem to be solved by the present application is: rapid real-time detection of hydrogen and methane at room temperature
In order to solve the technical problem, the technical scheme provided by the application is as follows:
TiO 2 selected as the semiconductor material for gas sensing. TiO 2 2 The nanoflower morphology of (a) makes it have a large specific surface area to support the Pd monoatomic atom. Pd monoatomic coordination on TiO 2 Nanoflower (expressed as Pd 1 -TiO 2 ) On the surface. The effective interface of Pd-O-Ti is through Pd atom and TiO 2 The surface coordination between the two is constructed to enhance the catalytic oxidation of hydrogen and methane at room temperature. Pd 1 -TiO 2 The sensor shows quick response and high sensitivity in hydrogen and methane detection.
TiO 2 Preparing the nanoflower: mixing TiCl 3 (1 mL) and ethylene glycol (20 mL) were mixed and stirred for 10 minutes, then 1mL of water was added. The light yellow solution was transferred to a teflon liner in a stainless steel autoclave and reacted at 160 ℃ for 6 hours. Followed by cooling to room temperature over 12 hours. Centrifuge at 8000rpm 5The product was obtained as a white product in minutes and further washed with water and ethanol. After drying in a vacuum oven, the TiO was collected 2 And (4) nano flowers.
Pd 1 -TiO 2 Preparing the nanoflower: first, 17.4mg of TiO was added 2 The nanoflower was dispersed in 10mL of water, then H was added with stirring 2 PdCl 4 Solution (0.845mL, 5mmol L) -1 ). The power density of the mixture exposed to light with stirring was about 10mW cm -2 For 5 minutes in 365nm ultraviolet light. Centrifugation gave a pale grey product, which was further washed with water. Pd 1 -TiO 2 The nanoflower were dried in a vacuum oven and collected.
Most current chemi-resistive sensors sensitive to methane and hydrogen require a test temperature, pd, of up to 150 degrees c or more 1 -TiO 2 Can be rapidly Pd at room temperature 1 -TiO 2 The method can rapidly and sensitively detect methane and hydrogen at room temperature, and has excellent sensitivity and reliable stability. Not only reduces energy consumption, but also is safer and more environment-friendly.
The beneficial effects that this application can produce include:
(1) Pd-TiO provided by the application 2 Application of surface coordinated single Pd atom based TiO in preparation of hydrogen and/or methane sensor 2 The method can quickly detect the methane and/or the hydrogen at a lower temperature, shows excellent sensitivity and reliable stability, reduces energy consumption, and is safer and more environment-friendly.
Drawings
FIG. 1 is Pd 1 -TiO 2 Dynamic response-recovery curve of device to methane with wide concentration (1-100 ppm)
FIG. 2 is Pd 1 -TiO 2 Device normalized response-recovery plot for methane concentration of 100ppm
FIG. 3 is Pd 1 -TiO 2 Double logarithmic graph of response value of device to methane concentration
FIG. 4 is Pd 1 -TiO 2 Dynamic response-recovery curve of device to hydrogen with wide concentration (1-100 ppm)
FIG. 5 is Pd 1 -TiO 2 Normalized response-recovery curve of device to hydrogen concentration of 100ppm
FIG. 6 is Pd 1 -TiO 2 Log-log plot of device response to hydrogen concentration
FIG. 7 shows Pd 1 -TiO 2 Response time and recovery time of device to different concentrations of hydrogen
FIG. 8 is Pd NPs-TiO 2 Dynamic response-recovery curve for 100ppm methane and 100ppm hydrogen at room temperature
FIG. 9 is TiO 2 Dynamic response-recovery curve of nanoflower at room temperature for 100ppm methane and 100ppm hydrogen
FIG. 10 is TiO 2 Nano flower and Pd 1 -TiO 2 And Pd NPs-TiO 2 Wherein a is TiO 2 B is Pd 1 -TiO 2 Transmission electron microscope image, c is Pd NPs-TiO 2 Transmission electron microscope image, d is Pd 1 -TiO 2 XPS image of (e) is Pd 1 -TiO 2 The aberration corrected high angle annular dark field STEM image of (1), f is Pd 1 -TiO 2 STEM-EDS element map of.
Detailed Description
The present application will be described in detail with reference to examples, but the present application is not limited to these examples.
The raw materials in the examples of the present application were all purchased commercially, unless otherwise specified.
In this application, the room temperature is (25. + -. 1). Degree.C.
Sensor test performance test systems reference the document Yao, m. -s.; tang, W. -X.; wang, G. -E.; nath, b.; xu, G., MOF Thin Film-Coated Metal Oxide Nanowire Array Significantly Improved Chemiers Sensor Performance. Adv. Mater.2016, 28, 5229-5234.
Morphological detail analysis adopted JSM-6700F type field emission scanning electron microscope of JEOL and TECNAI G2F 20 field emission transmission electron of FEIMicroscopy transmission electron microscopy. The high angle torroidal dark field scanning transmission electron microscope image and the aberration corrected high angle torroidal dark field scanning transmission electron microscope image are performed in a scanning transmission electron microscope model JEM-2100F of JEOL corporation equipped with a CEOS probe corrector. Data for X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy were obtained from Thermo Scientific ESCALAB 250Xi XPS system [ monochromatic Al K.alpha.X-rays (1486.6 eV), operating at 15kV, base pressure of 5.0X 10 –8 Pa]. The samples were first dried in a vacuum oven for 8 hours prior to XPS and UPS testing.
Palladium chloride [ PdCl ] used 2 ,98%]Purchased from Sigma Aldrich. Titanium (III) trichloride (15.0-20.0% TiCl% 3 Dissolved in 30% hcl) and Ethylene Glycol (EG) were purchased from Alfa Aesar. Hydrochloric acid (HCl-35%) and ethanol were purchased from Xin-weiche co.ltd. (fuzhou, china).
All aqueous solutions were prepared using Milli-Q water (18.2 M.OMEGA.). The Ag-Pd interdigital electrode plate with 200 mu m channels is purchased from Hangzhou Jinbokojic technology, inc. in China. The electrode plate was rinsed with water and dried with nitrogen before use.
Example 1
TiO 2 Preparing the nanoflower: mixing TiCl 3 Solution (15.0-20.0% TiCl) 3 Dissolve in 30% HCl) (1 mL) and ethylene glycol (20 mL) and mix and stir for 10 minutes, then add 1mL of water. The light yellow solution was transferred to a teflon liner in a stainless steel autoclave and reacted at 160 ℃ for 6 hours. Followed by cooling to room temperature over 12 hours. The white product was obtained by centrifugation at 8000rpm for 5 minutes, and further washed three times with 10mL of water and three times with 10mL of ethanol. After drying in a vacuum oven, the TiO was collected 2 And (4) nano flowers.
Pd 1 -TiO 2 Preparing the nano flower: first, 17.4mg of TiO was added 2 The nanoflower was dispersed in 10mL of water, then H was added with stirring 2 PdCl 4 Solution (0.845mL, 5mmol L -1 ). The power density of the mixture exposed to light with stirring was about 10mW cm -2 For 5 minutes in 365nm ultraviolet light. Centrifuging to obtain a light gray productAnd further washed with water. Pd 1 -TiO 2 The nanoflower were dried in a vacuum oven and collected.
Measurement of gas sensing performance: the gas sensor is manufactured using a conventional dispensing method. 1.0mg of prepared Pd 1 -TiO 2 The nanoflower sample was dispersed in 1mL of ethanol to obtain a dispersion. Subsequently, the dispersion containing 1.0mg of the sample was drop-coated on an Ag — Pd interdigitated electrode. Pd obtained 1 -TiO 2 The sensor was aged at 80 ℃ for 8 hours before testing. The sensor performance test conditions are as follows: constant gas flow 600mL min -1 The bias on the sensor was set to 5V and data was acquired using the Keithley 2602B source table. The target gas and the dry air are mixed according to a certain proportion through a mass flow controller to generate gas with accurate concentration, and then the gas is injected into a quartz tube. All tests were carried out at a temperature of (25. + -. 1). Degree.C. Pd 1 -TiO 2 The response (R) to the analyte is determined by detecting the change in resistance, defined as R (%) = (R) gas /r air -1). Times.100 reducing gas (wherein r air And r gas Are respectively Pd 1 -TiO 2 Electrical resistance in air and target gas). Pd 1 -TiO 2 The response and recovery time of (c) is the time required to achieve a 90% total resistance change.
As a result: using methane as a standard gas, pd 1 -TiO 2 The methane sensing performance of the device tested in a self-made gas sensing test device is shown in figures 1-3. FIG. 1 shows Pd 1 -TiO 2 Dynamic response-recovery curves for a wide range of 1 to 100ppm methane (specific concentrations of methane detected 1.0, 2.5, 5, 7.5, 10, 100 ppm) at room temperature. Pd 1 -TiO 2 The resistance of (a) significantly increased upon exposure to methane and returned to the initial value upon purging with dry air, indicating good reversibility. The prepared device has response value up to 3970% to methane with the concentration of 100 ppm.
From the normalized response recovery curve (FIG. 2), pd 1 -TiO 2 Exhibits very rapid response and recovery to methane gas at room temperature. Response to 100ppm methaneThe time is only 20 seconds and the recovery time is only 64 seconds. Pd was deduced by a linear fit of the plot by making a log-log curve of the concentration and response values, setting the response to 10% (fig. 3) 1 -TiO 2 The detection limit for methane at room temperature was as low as 0.815ppm.
Similarly, pd when tested with hydrogen as the standard gas 1 -TiO 2 The hydrogen sensing performance of the device tested in the home-made gas sensing test device is shown in fig. 4-7. From the hydrogen dynamic response-recovery curve (FIG. 4) of the wide concentration range of 1-100ppm (specific concentration of the detected hydrogen is 1, 3, 5, 10, 100 ppm), pd 1 -TiO 2 The device is very sensitive to hydrogen, the response value of the device increases along with the increase of the hydrogen concentration, and good reversibility is shown. The response value for hydrogen with a concentration of 100ppm is as high as 1209%. From the normalized corresponding recovery curve (FIG. 5) of hydrogen gas having a concentration of 100ppm, pd was found 1 -TiO 2 Exhibits a faster response and recovery to hydrogen gas at room temperature. The response time was 0.7 minutes and the recovery time was 5.52 minutes. Further, as is clear from FIG. 7, pd 1 -TiO 2 The device exhibits different response and recovery rates for different concentrations of hydrogen, faster response and recovery rates for low concentrations, and increased response and recovery times for higher concentrations of hydrogen. For example, for 1ppm hydrogen, the response time was only 0.37 minutes and the recovery time was 4.02 minutes, but as the hydrogen concentration increased to 100ppm, both the response time and the recovery time increased, 0.7 minutes and 5.52 minutes, respectively. In addition, by making a log-log curve of the hydrogen concentration and the response value, setting the response to 10% (fig. 6), a linear fit of the plot can deduce Pd 1 -TiO 2 The detection limit for hydrogen at room temperature was as low as 0.35ppm.
Comparative example 1
TiO 2 Preparing the nano flower: mixing TiCl 3 The solution (15.0-20.0% TiCl3 dissolved in 30% HCl) (1 mL) and ethylene glycol (20 mL) were mixed and stirred for 10 minutes, then 1mL water was added. The light yellow solution was transferred to a teflon liner in a stainless steel autoclave at 160 deg.cThe reaction is carried out for 6 hours. Followed by cooling to room temperature over 12 hours. The white product was obtained by centrifugation at 8000rpm for 5 minutes, and further washed three times with 10mL of water and three times with 10mL of ethanol. After drying in a vacuum oven, the TiO was collected 2 And (4) nano flowers.
Pd NPs-TiO 2 The preparation of (1): first, 17.4mg of TiO was added 2 The nanoflower was dispersed in 10mL of water, then H was added with stirring 2 PdCl 4 Solution (0.845mL, 5mmol L -1 ). The power density of the mixture exposed to light with stirring was about 10mW cm -2 And then irradiated with 365nm ultraviolet light for 30 minutes. Centrifugation gave a pale grey product which was further washed with water. NPs-TiO 2 The nanoflower were dried in a vacuum oven and collected.
Measurement of gas sensing performance: the gas sensor is manufactured using a conventional dispensing method. 1.0mg of prepared Pd NPs-TiO 2 The sample was dispersed in 1mL of ethanol to give a dispersion. Subsequently, a dispersion containing 1.0mg of the sample was drop-coated on an Ag-Pd interdigitated electrode. Obtained Pd NPs-TiO 2 The sensor was aged at 80 ℃ for 8 hours before testing. The sensor performance test conditions are as follows: constant gas flow 600mL min -1 The bias on the sensor was set to 5V and data was acquired using the Keithley 2602B source table. The target gas and the dry air are mixed according to a certain proportion through a mass flow controller to generate gas with accurate concentration, and then the gas is injected into a quartz tube. All tests were carried out at a temperature of (25. + -. 1). Degree.C. Pd NPs-TiO 2 The response (R) to the analyte is determined by detecting the change in resistance, defined as R (%) = (R) gas /r air -1). Times.100 reducing gas (wherein r air And r gas Are each Pd NPs-TiO 2 Electrical resistance in air and target gas). Pd NPs-TiO 2 The response and recovery time of (c) is the time required to achieve a total resistance change of 90%.
As a result: using methane and hydrogen as standard gases, pd NPs-TiO 2 The methane sensing performance of the device is shown in fig. 8. FIG. 8 shows Pd NPs-TiO 2 Dynamic response recovery to methane concentration of 100ppm and hydrogen concentration of 100ppm at room temperatureA complex curve. Pd 1 -TiO 2 The resistance of (a) significantly increased upon exposure to methane, hydrogen and returned to the initial value upon purging with dry air, indicating good reversibility. However, pd NPs-TiO 2 The response value of the device to 100ppm methane gas is only 53 percent, and Pd 1 -TiO 2 In contrast, the response value decreased by a factor of 75. Pd NPs-TiO 2 The response value of the device to 100ppm hydrogen is only 21.6 percent, and Pd 1 -TiO 2 In contrast, the response value decreased by 56 times.
Comparative example 2
TiO 2 Preparing the nano flower: mixing TiCl 3 The solution (15.0-20.0% TiCl3 dissolved in 30% HCl) (1 mL) and ethylene glycol (20 mL) were mixed and stirred for 10 minutes, then 1mL water was added. The light yellow solution was transferred to a teflon liner in a stainless steel autoclave and reacted at 160 ℃ for 6 hours. Followed by cooling to room temperature over 12 hours. The white product was obtained by centrifugation at 8000rpm for 5 minutes, and after washing three times with further 10mL of water, it was washed three times with further 10mL of ethanol. After drying in a vacuum oven, the TiO was collected 2 Nanoflowers were used for characterization and further experiments.
Measurement of gas sensing performance: the gas sensor is manufactured using a conventional dispensing method. 1.0mg of the prepared TiO 2 The nanoflower samples were dispersed in 1mL ethanol. Subsequently, a dispersion containing 1.0mg of the sample was drop coated on the Ag — Pd interdigitated electrode. Obtained TiO 2 The nanoflower sensors were aged at 80 ℃ for 8 hours before testing. The sensor performance test conditions are as follows: constant gas flow 600mL min -1 The bias on the sensor was set to 5V and data acquisition was performed using the Keithley 2602B source table. The target gas and the dry air are mixed according to a certain proportion through a mass flow controller to generate gas with accurate concentration, and then the gas is injected into the quartz tube. All tests were carried out at a temperature of (25. + -. 1). Degree.C. TiO 2 2 The response (R) of the nanoflower to the analyte was determined by detecting the change in resistance, defined as R (%) = (R) gas /r air -1). Times.100 reducing gas (wherein r air And r gas Are respectively TiO 2 Electricity of nanoflower in air and target gasResistance). TiO 2 2 The response and recovery time of the nanoflower is the time required to reach 90% of the total resistance change.
As a result: methane, hydrogen as standard gases, tiO 2 The methane sensing performance of the nanoflower device test is shown in fig. 9. FIG. 9 shows TiO 2 The dynamic response-recovery curve of nanoflower at room temperature for methane concentration of 100ppm and hydrogen concentration of 100 ppm. TiO 2 2 The nanoflower resistance increased significantly upon exposure to methane, hydrogen, and returned to the initial value upon purging with dry air, indicating good reversibility. However, tiO 2 The response value of the nanoflower device to 100ppm methane gas is only 17.04 percent, and the response value is equal to that of Pd 1 -TiO 2 In contrast, the response value decreased 233 times. TiO 2 2 The response value of the nanoflower device to 100ppm hydrogen is only 16.31 percent, and the reaction value is Pd 1 -TiO 2 In contrast, the response value decreased by a factor of 74.
And (3) characterization: tiO 2 2 The scanning electron microscope measurement of (a) shows similar nanoflower morphology with particle size of 100-500 nm (fig. 10 a). From transmission electron microscope images, in Pd 1 -TiO 2 Pd NP was not found in (FIG. 10 b). In contrast, in Pd NPs-TiO 2 Can be found in 5nm Pd particles (FIG. 10 c), which show 0.221nm lattice fringes, belonging to the d111 spacing of Pd NPs. Pd 1 -TiO 2 The aberration corrected high-angle annular dark field STEM image shows that the ultra-small bright points are uniformly dispersed in TiO 2 On the nanoflow (fig. 10 e), it is shown that the Pd species exists as isolated single atoms. Pd 1 -TiO 2 STEM-EDS elemental map of (fig. 10 f) shows that Ti, O and Pd elements are well distributed throughout the nanoflower. In XPS, pd 1 -TiO 2 The Pd3d spectrum of (3 d) shows two main signals 5/2 And 3d 3/2 ) At 336.2 and 341.4eV, respectively, between Pd 2+ And Pd 0 In between, indicating that the part is in the oxidized state anchoring the Pd atoms (fig. 10 d).
The measurement of ICP-AES (inductively coupled plasma-atomic emission Spectroscopy) shows Pd 1 -TiO 2 Middle Pd 1 Loading of 0.34wt.%.
Although the present invention has been described with reference to a few preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. Pd-TiO 2 Use in the preparation of a hydrogen and/or methane sensor, characterized in that the Pd-TiO is 2 Comprising Pd monoatomic and TiO 2
The Pd monoatomic atom is coordinated on the TiO 2 Of (2) is provided.
2. Use according to claim 1, wherein the monoatomic Pd is a +1 valent Pd monoatomic Pd 1
3. Use according to claim 1, characterized in that the TiO is 2 The appearance of (A) is nano flower.
4. Use according to claim 1, characterized in that the TiO is 2 The particle diameter of (A) is 100 to 500nm.
5. Use according to claim 1, wherein the Pd-TiO is 2 Wherein the load of the Pd monoatomic atom is 0.1 to 5wt.%.
6. The use according to claim 1, characterized in that the detection conditions of the sensor comprise:
the temperature is 20-30 ℃.
7. The use according to claim 1, wherein the detection conditions of the sensor comprise:
the temperature is 23-26 ℃.
8. The use according to claim 1, wherein the detection conditions of the sensor comprise:
the bias voltage is 1-5V.
9. The use according to claim 1, wherein the detection conditions of the sensor comprise:
detecting the airflow of 200-600 mL min -1
10. The use of claim 1, wherein the sensor has a methane detection limit of as low as 0.815ppm at 25 ± 1 ℃;
the limit of detection of the sensor for hydrogen is as low as 0.35ppm.
CN202110970120.4A 2021-08-23 2021-08-23 Pd-TiO 2 Application in preparation of hydrogen and/or methane sensor Pending CN115711921A (en)

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